Aqueous, agrochemical agents containing active ingredients

ABSTRACT

An aqueous agricultural composition containing: (a) at least one water-insoluble agrochemical; and (b) an additive corresponding to formula (I): 
     
       
         RO—(C 2 H 4 O) n (C 3 H 6 O) m —R′  (I) 
       
     
     wherein RO is an alcohol selected from the group consisting of branched or linear, saturated or unsaturated monohydric alcohols having from 1 to 6 carbon atoms or polyols having from 2 to 12 carbon atoms and from 2 to 6 hydroxyl groups, and R′ is hydrogen or an ester group —CO—R″ wherein R″ is a branched or linear, saturated or unsaturated alkyl group having from 5 to 20 carbon atoms, m is a number from 1 to 10 and n is a number up to 40, and wherein the agrochemical and the additive are present in a ratio by weight of from 1:2 to 1:5.

The application is a 371 of PCT/EP99/03328 filed May. 14, 1999.

BACKGROUND OF THE INVENTION

This invention relates to water-based compositions which contain atleast one agricultural chemical (“agrochemical”) and certain alkoxylatedfatty acids esters, to the use of such fatty acid esters for theproduction of compositions containing agrochemicals and to a process forapplying agrochemicals to plants.

There are various known agents for protecting crops against pests andweeds. Unfortunately, they often show little or no solubility in water.Accordingly, these products are often marketed in the form ofcompositions based on mineral oils. On account of the environmentalproblems this involves and particularly on account of the inadequatebiodegradability of the solvent, attempts are now being made to stopusing these products. Instead, the agrochemicals are formulated as anaqueous dispersion or emulsion and may thus be readily be applied to theplants, for example by spraying.

Numerous auxiliaries are known to the expert for dispersing oremulsifying various active substances in water. In order to obtainstable dispersions or emulsions, however, very intensive shear forcesoften have to be applied in the production of the compositions. Inaddition, separation of the emulsion or dispersion can occur in theevent of significant temperature differences during the storage and useof the compositions. In many cases, the plant protection compositionsare also marketed as concentrates which are only diluted to the requiredextent in situ. In cases such as these, however, machines suitable forobtaining compositions in the required, stably emulsified form, such ashigh-speed mixers, are often not available.

Accordingly, WO 96/22109 describes the use of ethoxylated fatty acidesters having certain HLB values for the production of plant protectioncompositions or pharmaceutical preparations. These esters arebiodegradable and self-emulsifying. However, plant protectioncompositions containing these esters as emulsifiers do not always havesufficient stability, particularly at high temperatures. Accordingly,there is still a need for water-based plant protection compositionswhich are stable in storage, even at high temperatures, and which areeasy to produce.

It has surprisingly been found that compositions containingagrochemicals and certain propoxylated fatty acid ester as dispersantsor emulsifiers satisfy the above-mentioned requirements in regard tostability and handling behavior.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention relates to water-based compositionscontaining water-insoluble agrochemicals and one or more compoundscorresponding to general formula (I):

RO—(C₂H₄O)_(n)(C₃H₆O)_(m)—R′  (I)

in which RO is an alcohol selected from the group of branched or linear,saturated or unsaturated monohydric alcohols containing 1 to 6 carbonatoms or polyols containing 2 to 12 carbon atoms and 2 to 6 hydroxylgroups and R′ is hydrogen and/or a group —CO—R″, where R″ is a branchedor linear, saturated or unsaturated alkyl group containing 5 to 29carbon atoms, m is a number of 1 to 10 and n is 0 or a number of 1 to40.

The compositions according to the invention may contain both solid andliquid water-insoluble ingredients. Accordingly, they form bothdispersions and emulsions. In the present specification, dispersions andemulsions are collectively referred to as dispersions.

DETAILED DESCRIPTION OF THE INVENTION

The alkoxylated fatty acid esters corresponding to formula (I) are knownsubstances which are described, for example, in U.S. Pat. No. 2,678,935,U.S. Pat. No. 3,539,518, U.S. Pat. No. 4,022,808 and GB 1,050,497, ofwhich the disclosures are also part of the present application.

The alkoxylated fatty acid esters may be prepared by any methods knownto the expert, for example by esterification of fatty acids withalkoxylated methanol, as described in U.S. Pat. No. 3,539,518.Unfortunately, this process has certain disadvantages, i.e. it comprisestwo steps, the esterification step takes a very long time and theproducts are colored by the high reaction temperatures. In addition,correspondingly produced fatty acids methyl ester ethoxylates haverelatively high OH values after esterification which can beproblematical for certain applications. Another method comprisesdirectly reacting fatty acid esters with alkylene oxide in the presenceof transition metal catalysts (cf. U.S. Pat. No. 4,022,808). However,the fatty acid alkyl ester alkoxylates are preferably produced by theheterogeneously catalyzed direct alkoxylation of fatty acid alkyl esterswith ethylene oxide and/or propylene oxide on calcined orhydrophobicized hydrotalcites. This synthesis process is described indetail in WO 90/13533 and WO 91/15441, of which the disclosure is alsopart of the present application. The products obtained are distinguishedby the low OH value, the reaction is carried out in a single stage andlight-colored products are obtained. The fatty acid alkyl esters servingas starting materials may be obtained from natural oils and fats or maybe synthesized.

The alkoxylated fatty acid esters contain at least 1 mole of propyleneoxide groups per mole of ester. Compounds of formula (I) which containbetween 1 and 10 moles of propylene oxide per mole of ester arepreferred. In addition to the propylene oxide units, between 1 and 40ethylene oxide groups are also preferably present in the molecule.Compounds corresponding to formula (I) containing between 1 and 30 molesof ethylene oxide per mole of ester are preferred. Both compounds whichhave been reacted with a mixture of ethylene oxide and propylene oxideand compounds which have been reacted with ethylene oxide and propyleneoxide in two separate steps may be used as these mixed ethyleneoxide/propylene oxide adducts. Where compounds of formula (I) whichcontain polyols as the alcohol component RO are used, the quantity datarelating to the ethylene or propylene oxide units (indices n and m) arealways based on the molecule as a whole. However, it is known that theexact distribution of the ethylene or propylene oxide units among thevarious hydroxyl groups obeys a distribution dependent on the synthesis.

The fatty acid esters —CO—R″ contain alkyl groups R″ with 5 to 29 carbonatoms. Suitable fatty acid components are natural and synthetic fattyacids, more particularly straight-chain, saturated or unsaturated C₆₋₃₀fatty acids, including the technical mixtures thereof obtainable bylypolysis from animal and vegetable fats and oils, for example fromcoconut oil, palm kernel oil, soybean oil, sunflower oil, rapeseed oil,cottonseed oil, fish oil, bovine tallow and lard; special examples arecaprylic acid, capric acid, lauric acid, lauroleic acid, myristic acid,myristoleic acid, palmitic acid, palmitoleic acid, oleic acid, elaidicacid, arachic acid, gadoleic acid, behenic acid and erucic acid.

The alcohol component RO may be selected from linear or branched,saturated or unsaturated monoalcohols containing 1 to 6 carbon atoms,for example methanol, ethanol, n- and i-propanol, n- and i-butanol,pentanol, hexanol, 2-ethylhexanol and cyclohexanol. Suitable polyolscontaining 2 to 6 carbon atoms are, for example, ethylene glycol,1,2-propylene glycol, 1,2-butylene glycol, glycerol or trimethylolpropane and pentaerythritol. Basically, all the hydroxyl groups of thealcohols are substituted by the alkoxides, although the terminalalkoxide groups are not all end-capped by ester groups. Accordingly, ifpolyols, such as glycerol or ethylene glycol, are used as the alcoholcomponent RO, the compositions may contain compounds of formula (I)obtained by reaction of the full esters and also the partial esters withalkoxides. However, preferred compounds corresponding to formula (I) arethose in which all the hydroxyl groups of the alcohols are alkoxylatedand all terminal alkoxide groups are endcapped by ester groups with theformula —CO—R″. Accordingly, in these preferred compounds, thesubstituent R″ in formula (I) is exclusively a branched or linear,saturated or unsaturated alkyl group containing 5 to 29 carbon atoms.

In addition, alkoxylated fatty acid esters corresponding to formula (I)of which the fatty acid component is selected from linear unbranchedC₆₋₁₈ fatty acids and of which the alcohol component is methanol, theesters of formula (I) preferably containing between 1 and 3 moles ofpropylene oxide and between 1 and 6 moles of ethylene oxide per mole ofester, are preferably used in the compositions according to theinvention. Compounds such as these may be obtained, for example, by theabove-described reactions of palmitic, stearic, oleic, linoleic orlinolenic acid, lauric acid and myristic acid or esters thereof withalkoxides.

Also suitable are alkoxylated esters where the alcohol component isglycerol and the fatty acid component is selected from saturated orunsaturated, branched or unbranched fatty acids containing 18 to 22carbon atoms and the esters contain between 3 and 10 moles of propyleneoxide per mole of ester. Compounds of formula (I) additionallycontaining between 1 and 30 moles of ethylene oxide per mole of esterare particularly preferred. Compounds such as these may be obtained, forexample, by reacting glycerol esters of natural fatty acids, such as forexample palm oil, rapeseed oil or preferably castor oil, with ethyleneoxide.

The compounds corresponding to formula (I) present in the compositionsaccording to the invention are nonionic compounds which may beadditionally characterized by their HLB value (hydrophilic-lipophilicbalance as defined by Griffin, cf. Römpp, Lexikon Chemie, 10th Edition1997, page 1764). Preferred compositions contain compounds of formula(I) with HLB values of 4 to 10 and, more particularly, 5 to 9.

The agrochemicals present in the compositions according to the inventionare insoluble or only sparingly soluble in water at room temperature(21° C.). Sparingly soluble means that less than 10% by weight issoluble in water, more particularly less than 1% by weight. Theagrochemicals may be solid or liquid at room temperature. In the contextof the present invention, agrochemicals are understood to be substancessuitable for plant protection and also herbicides and fertilizers. Plantprotection agents also include insecticides, acaricides, nematicides andalso repellents and rodenticides, sexual attractants, animal and birddeterrents and chemical sterilizers as described, for example, in Chemieder Pflanzenschutz- und Schädlingsbekämpfungsmittel, Vol. 1, Editor: R.Wegler, Springer Verlag Berlin, 1970. Depending on the agrochemicalused, the compositions may have to be adjusted to a certain pH valueoptimal for the particular agrochemical.

The compositions contain at least one water-insoluble agrochemical,although mixtures of different agrochemicals may also be used. Thecompositions according to the invention may contain the agrochemicalboth in concentrated form, in which case they are formulated asconcentrates containing more than 50% by weight to at most 90% by weightof agrochemical, and also in dilute form. Compositions containingbetween 0.1 and 10% by weight of agrochemicals, based on the weight ofthe composition, are preferred. The compositions according to theinvention preferably have a water content of 10 to 90% by weight.

The dispersions according to the invention generally contain only smallquantities —normally between 0.1 and 15% by weight—of compoundscorresponding to formula (I). The quantity ratio between the compoundsof formula (I) and the agrochemicals is preferably between 1:1 and1:100. Particularly preferred compositions are characterized in that theratio by weight between the compounds corresponding to formula (I) andthe agrochemicals is in the range from 1:10 to 1:80 and moreparticularly in the range from 1:2 to 1:5.

Besides the agrochemicals and the compounds corresponding to formula(I), the water-based compositions according to the invention may containother typical ingredients and additives, including solvents, such asethylene and propylene glycols and C₁₋₆ alcohols, solid carriermaterials, such as lignin, lignin derivatives or clays, and other knownemulsifiers and dispersants. The dispersions may also additionallycontain water-soluble agrochemicals. However, particularly preferredcompositions are characterized in that they only contain emulsifierscorresponding to formula (I), i.e. no other emulsifiers or dispersants.The compositions according to the invention are stable in storage, evenat temperatures above 30° C., and may be prepared without having toapply intensive shear forces, for example by manual stirring.

The present invention also relates to the use of compounds correspondingto formula (I) for the production of water-based compositions containingwater-insoluble agrochemicals, at least one agrochemical being dispersedor emulsified in water together with compounds corresponding to formula(I).

The compositions according to the invention are formed without theapplication of intensive shear forces, for example simply by manualstirring. To this end, the compounds corresponding to formula (I) may beintroduced first, for example in liquid form. The agrochemical is thenadded and the resulting mixture is dispersed in water. If compoundscorresponding to formula (I) with melting points above room temperatureare used, they may be used in molten form. However, compounds of formula(I) with a melting point below 25° C. are preferably used. It is alsopossible, however, initially to prepare a mixture of the agrochemical inwater and then to emulsify or disperse the resulting mixture by additionof compounds corresponding to formula (I).

The present invention also relates to a process for treating plants withagrochemicals in which an aqueous dispersion as described in theforegoing is applied to plants in known manner, more particularly byspraying.

EXAMPLE

A water-based plant protection emulsion was prepared by mixing 50 g ofthe insecticide allethrin with the same quantity by weight of a rapeseedoil propoxylated with 3 moles propylene oxide and then ethoxylated with30 moles ethylene oxide (by the method according to WO 90/13533) andemulsifying the resulting mixture with 900 g of tap water simply bystirring at room temperature. The emulsion thus obtained was stable instorage for more than 24 hours at 40° C.

What is claimed is:
 1. An aqueous agricultural composition consistingessentially of: (a) at least one water-insoluble agrochemical; and (b)an additive corresponding to formula (I):RO—(C₂H₄O)_(n)(C₃H₆O)_(m)—R′  (I) wherein RO is an alcohol selected fromthe group consisting of branched or linear, saturated or unsaturatedmonohydric alcohols having from 1 to 6 carbon atoms or polyols havingfrom 2 to 12 carbon atoms and from 2 to 6 hydroxyl groups, and R′ ishydrogen or an ester group —CO—R″ wherein R″ is a branched or linear,saturated or unsaturated alkyl group having from 5 to 29 carbon atoms, mis a number from 1 to 10 and n is a number up to 40, and wherein theagrochemical and the additive are present in a ratio by weight of from1:2 to 1:5.
 2. The composition of claim 1 wherein in formula I RO is aglycerol residue and R″ is a branched or linear, saturated orunsaturated alkyl group having from 17 to 29 carbon atoms.
 3. Thecomposition of claim 1 wherein in formula I m is a number from 1 to 6and n is a number from 1 to
 30. 4. The composition of claim 1 wherein informula I m is a number from 1 to 3 and n is a number from 1 to
 6. 5.The composition of claim 1 wherein in formula I —CO—R″ is a ricinoleicacid residue and RO is a glycerol residue.
 6. The composition of claim 1wherein in formula I RO is a methanol residue and R″ is a branched orlinear, saturated or unsaturated alkyl group having from 5 to 17 carbonatoms.
 7. The composition of claim 1 wherein the agrochemical is presentin the composition in an amount of from 0.1 to 10% by weight, based onthe weight of the composition.
 8. The composition of claim 1 wherein theadditive of formula I has an HLB value of from 4 to
 10. 9. The processof claim 1 wherein the additive of formula I has an HLB value of from 4to
 10. 10. A process for treating plants comprising contacting theplants with a composition consisting essentially of: (a) at least onewater-insoluble agrochemical; and (b) an additive corresponding toformula (I): RO—(C₂H₄O)_(n)(C₃H₆O)_(m)—R′  (I) wherein RO is an alcoholselected from the group consisting of branched or linear, saturated orunsaturated monohydric alcohols having from 1 to 6 carbon atoms orpolyols having from 2 to 12 carbon atoms and from 2 to 6 hydroxylgroups, and R′ is hydrogen or an ester group —CO—R″ wherein R″ is abranched or linear, saturated or unsaturated alkyl group having from 5to 29 carbon atoms, m is a number from 1 to 10 and n is a number up to40, and wherein the agrochemical and the additive are present in a ratioby weight of from 1:2 to 1:5.
 11. The process of claim 10 wherein informula I RO is a glycerol residue and R″ is a branched or linear,saturated or unsaturated alkyl group having from 17 to 29 carbon atoms.12. The process of claim 10 wherein in formula I m is a number from 1 to6 and n is a number from 1 to
 30. 13. The process of claim 10 wherein informula I m is a number from 1 to 3 and n is a number from 1 to
 6. 14.The process of claim 10 wherein in formula I —CO—R″ is a ricinoleic acidresidue and RO is a glycerol residue.
 15. The process of claim 10wherein in formula I RO is a methanol residue and R″ is a branched orlinear, saturated or unsaturated alkyl group having from 5 to 17 carbonatoms.
 16. The process of claim 10 wherein the agrochemical is presentin the composition in an amount of from 0.1 to 10% by weight, based onthe weight of the composition.